With the nervous analyses and speculation gripping music technology of late, almost any new developments in marketing or software give rise to far-flung prophecies of change.

Subscription download services, desperately searching for a legal middle ground, have been hailed as a balance between piracy and over-priced CDs. Satellite radio and free or pay-what-you-please albums experience their share of commentary, as in the case of Radiohead, Nine Inch Nails and Stars.

As was probably to be expected, not all of the supposed advances were meant to outlast the hype and become reality. With some experiments, like the Radiohead/Nine Inch Nails/Stars idea, it’s probably too early to tell, but others, like subscription downloading, can safely be pronounced as a poor solution. Navigating copyright issues complicated the attempts to set up a comprehensive selection, and the motivation to use the service was purely moral.

Less music, for money, didn’t strike many as a step forward. Satellite radio may change the way people engage in music with its wide selection of artists and genres but not until it is installed in every car stuck in rush-hour traffic.

But what is truly a lasting advance in music technology of the last couple years – 2006, to be precise – is marketing and previewing music through MySpace. It won’t solve the problem of downloading, but it has lived up to the forecasts.

Two years since launching, everybody’s on MySpace Music, even hippies like Santana and jazzers like Herbie Hancock, who have already had full careers. And if you aren’t already using MySpace to fact-check your friends’ musical name-dropping, or just to get a preview of what some band sounds like, it’s time you started.

It’s easy to see why the idea of full preview songs posted online was to be a lasting one. Who doesn’t remember a record store experience of overwhelming proportions, with esoterically named genres marking row after row, where the one band you do know could be either in the IDM or the MFB section – the event, on the whole, depressing in its enormity? The only way to hear the music was to buy it.

Reading the critics has always been another way to get a sense of what’s going on in a band and to grasp their larger context, but when all the language, metaphors and attitude that characterize, say, a typical Pitchfork review get tiring, substituting sounds for words couldn’t be more simple.

On MySpace, self-made artists receive incredible exposure for little or no cost, and listeners have an immediate, unadulterated filter through which to trim the fat of the myriad musical acts hyped on a daily basis. If you like the stuff, you can buy it online, go to the record store with an idea of what you’re doing, or, more likely, download it. You won’t have to waste your hard drive on something you didn’t want anyway.

Think back to the record store, and the reason why this innovation has lasted over time becomes apparent.

Apart from the six or so featured albums customarily provided for preview listening, the sea of silent carriers of music, those muted plastic discs, loom at the directionless customer. You could ask the snobby clerk and get the Jack Black-in-High Fidelity treatment if your taste doesn’t hit the mark. Or, you could look it up on MySpace.